Torpedo hub nut



Nov. 11, 1958 D. M. MYERS 2,859,722

ToRPEDo HUB NUT Filed Dec. 5, 1956 2 Sheets-Sheet 1 u FIG. 1

` DA VID M. MYERS INVEN TOR.

Nov. ll, 1958 D. M, MYERS 2,859,722 ToRPEDo HUB NUT Filed Dec. 5, 1956 2 Sheets-Sheet 2 DA VID M. M YE RS 5 INVENTOR. 2

' ATTQWVEYQ States assignments, Vto the United States of America as represented by the Secretary of the Navy Application December 5, `1956, Serial N0.\626, 561 9 Claims. (Cl. 114-20) This invention relates tto propeller hub nuts `for .torpedos .and more particularly y:to a hub nut `for Yuse on steam torpedos Ahaving va :hollow propeller Yshaft through .which gases 1are exhausted.

:in most Vinstances vwhere torpedos are launched from -Xed Wing aircraft the torpedo is launched .at `an 'altitude of about ,350 feet and lat a speed of about Z50-,3.00 knots and the torpedo is provided with a parachute at its rear end tostabilize and Areduce the speed of the torpedo during its air travel to insure proper water entry conditions. lt is -essential in such .cases that `the `parachute `be released at substantially the instant the ,torpedo strikes the surface of the Water. Various release `devices that utilize the impact of the torpedo striking the Water to initiate action ofthe release mechanism have been developed to secure -the release of the parachute.

It has been found `that a torpedo provided with a parachute and air launched in the conventional `manner enters the water at `-a speed of about 190-195 knots and that .during descent the torpedo does not follow a Vtrue trajectory 'but wobbles `or tends to `oscillare about the point Where the parachute is connectedV to the torpedo `body. The amount of `vwobble `and the length of time through which it extends is dependent upon the altitude of the torpedo when it isreleased. In view of this it may be obvious `that the parachute release device `and the means for connecting it to `the torpedo are subjected `to substantial stresses and `bending moments and hence must be Ofsufficient sizeand configuration ,as to resist such forces.

For the special case of the so-called steam torpedo, i. e., a torpedo having a turbine prime mover wherein `theturbine exhaust gases such as steam and the li-ke are exhausted through a hollow propeller shaft, not only must the connecting means and the release means be structurally strong but their combination must not result n the creation of a back pressure on the turbine. Still further, for optimum operation, the connecting means must have a hydrodynamic configuration that will not effect the operation or eiciency of 4theprcnaeller and Vthat will operate most eectively in its environment.

vIn general, toi-pedos utilizing an electric motor as a prime mover have solid propeller shafts having a knob like projection formed on their rear surface to facilitate removal of such a torpedo from a launching tube such as for example when it fails to operate or it is decided 'not to fire the torpedo. However, heretofore no such means have been provided for steam torpedos and the removal of such torpedos from a launching tube is thereforemore difficult and often results in damage or injury to the torpedo, its appendages or propeller blades.

lt is accordingly an object of the present invention to provide a more versatile and substantially improved construction for steam torpedo hub nuts.

Another object of the present invention is the provision ofa versatile hub nut for steam toi-pedos that may be permanently installed at the place of manufacture to eliminate the need for modification of the torpedo land/or the manufacture, provision and installation `of separate .2,859,722 Patented Nov. 11, 19598 means to aiiix-a parachute to the torpedo for launching' from' fan airborne body. l,

Another object Vof the present invention is th'eprovisi'on of a-hub nut-of simple construction-'for steam'torpedos that provides a point of attachment for a parachute concentric about fthe `longitudinal axis of the 4propeller shaft and which provides ahig'h degree of s'tructural'strength, hydrodynamic designand simplicity for optimum exhaust conditions.

Still Yanother object of the present Vinvention is 'the provision of a hub nut for'steam torpedos that "in addition to providing a lp'o'intof attachment for `a parachute provides a new and Iriove'l means f'fordistributing and directing exhaust gases-thereby 'resulting in a faster and a less violent mixing of the exhaust Ivgases and the water.

Another object-of'thepresent invention is theprovis'ion of a hub nut for steam torpedos that `will `facilitate Athe 'removal of a steam torpedo after it 'has ibeen Iinserted in a launching tube. Y

hThese and other objects and features of the invention, together with their incident advantages, will be more readily understood and appreciated from the following detailed description of the preferred embodiment thereol:` selected for purposes of illustration and `shown in the accompanying drawings, in which:

Figure 1 is an lelevation view illustrating the hub nut incorporating the Ypresent invention mounted on` a torpedo and showing a parachute harness attached to the .hub nu't.

Figure 2 is a rear view with a `portion broken away of a hub nut constructed ,according to the present invention.

Figure 3 is a `sectional View taken on line 3 3 of Figure 2.

A hub nut 10 constructed according to the present invention is shown in Figure 1 mounted on the rear portion of a propeller shaft `11 of `a conventional steam torpedo '12 utilizing a propeller 13 (shown in phantom) in the vconventional manner. Attached to the rear surface of the hub nut is a parachute harness 14 also .shown in phantom `and an impact release .mechanism 15 shown partly in section. The propeller, propeller shaft, parachute harness and impact release mechanism form n o part of the present invention and are shown -only for the purposes of illustration and to show the relation` of the hub nut to a torpedo and a parachute harness. A

Parachute .impact release mechanisms, an example` of Which is shown in Figure .1, used with air launched `torpedos are generally of the type comprising an inner sleeve 16 permanently attached to the torpedo and disposed Within` an outer sleeve 17, the outer sleeve 17 being telescopically mounted on the -inner sleeve 16 and fixed with relation thereto and the Yparachute harness 14 by impact releasing means comprised of balls 18 carried in sleeve 116, a grooved rotatable projection 19 and a groove 21 formed in the inner surface 4of sleeve 17 to .receive -the halls 18, which, upon suicient decelerationof the torpedo, is activated and allows separation of the outer sleeve 17 and the parachute harness 14 from the inner sleeve 16, the inner sleeve 16 remaining attached to the torpedo.

As best shown in Figure 1 and Figure 3 the present invention is comprised of a moreor less hollow hub .nut 1i) open at its forward end 22 and having a general outer configuration of a frustrum of a cone having a conical side wall 23 `and a rear wall `24 transverse to the longitudinal axis of the hub nut. The numeral 2S designates a forwardly extending front surface adapted for abutting relationship with the propeller 13, the inner front surface 26 being recessed or relieved .in a manner well known in the art to facilitate and insure proper mating of the front surface 25 and the rear surface 27 of the propeller 13. Provided in the front portion. of the hub nut is an internally threaded cylindrical -recress 28 concentric about the longitudinal axis of the hub nut and adapted for engagement with an externally threaded rear portion of the propeller shaft 11. Disposed rearwardly ofireeessj 2 8` is ja similar cylindrical recess v31 having a smooth cylindrical inner surface 32 and a diameter substantially equal to the internal diameter ofthe propeller shaft, whereby .when the hub nut is threaded onto a hollow propeller shaft of the proper inter-nal diameter -the inner-cylindrical surface -32 of recess 31 is contiguous )Vith anda continuation of the smooth inner surface of the hollow propeller shaft. There is provided in the rear portion of the side wall 23 a plurality of exhaust ports 33 adapted to receive and direct the exhaust gases in an out- Y ,wardly-andrearwardly*directions L* Each exhaust port 33 is comprised of a front surface 34'=and'a rear` surface 35 lying inwardly and forwardly extending preferably parallel `conical surfaces at an angle 4of substantially 60 degrees to and concentric about the Ylongitudinal axis.- VSurfaces A34--35 are connected by oppositely disposed-radial surface 36.

, The exhaust ports 33 (asbest shown-in'Figure 2) are radially disposed about the longitudinal axis of the hub nut and are separated by rearwardly extending segments orI wall -portions 37 integral with the forward portion of the hub nut and the rear wall 24. It has been found -that for a conventional propeller shaft having an internal `diameter of about 2.3 inches if the exhaust ports 33 a-re disposed at an angle of about 60 degrees to the longitudinal axis and extend through an are of about 60 degrees, each exhaust port 33 Vwill be separated by a wall portion 37 ,whose sides 36 yare disposed apart by va radial angle of .about 30 degrees, thereby imparting to the hub nut sufficient strength and optimum exhaust conditions. 4 To facilitate formation of the hub nut it isdesirable that the inner periphery of the rear surface 35 of each exhaust portbe formed at the junction 38 of the outer periphery of the inner rear wall surface 39 and the rear Y'periphery of the cylindrical surface 32. of recess 31.

1t isV to be noted that although the preferred embodiment asVV described herein utilizes four exhaust ports having'thelocations and dimensions as described hereinabove it isfo be vunderstood that for propeller shafts having 'greater'or'lesser' internalk diameters variation in the 'number of, exhaust ports rand their location and dimensions are possible.

@Itis importanhhowever, that the total area of the exhaust ports 33 at the' cylindrical surface 32 of recess I31 be substantially equal to and preferably greater than Ithe'interr'lal area of the propeller shaft 11. Radial formatiojnoflthe sides 36 of 'the exhaust ports is preferable to 'allow'Y continued expansion of the exhaust gases as they pass through the exhaust ports thereby preventing any back vpressure due to the exhaust gases passing through the vexhaust ports and to facilitate formation of the exhaust ports as by casting or machining.

As mentioned previously hereinabove, for steam torpedos provided with a hollow propeller shaft having an internal diameter of about 2.3 inches the exhaust ports 33 should preferably be formed at a rearward angle of 60 degreesto the longitudinal axis and extend through an are of about 60 degrees, the total area of the exhaust ports33 at surface 32 being at least equal to the internal v area of the propeller shaft. s

* lIt should be noted, however, that substantial deviations from the preferred direction and radial length of the exhaust ports as indicated hereinabove, fora propeller shaft having substantially the same internal area, will seriously 'weaken the hub nut .and/oriinterfere with exhausting of the turbine gases. The total area of the exhaust ports will; of course, depend on the longitudinal distance between surfaces 34-35 which in turn is substantially dependent upon the longitudinal length of the rear portion v 44 should be such that the forward surface of the conical l' 4nut will tend to tighten the parachute vrelease mechanism exhaust ports is dependent upon several factors and that the internal area of the exhaust ports should have a total area asindicated hereinabove with a sufficient amount of side wallmaterial between them to insure that such wall portions will have suticient shear strength that they will not crack or break at or after the opening of the stabiliz- Y f o' ing parachute.

The rear portion of the hub nut 10 is closed by a Y Q transverse rear wall 24 having substantially co-planar front and rear surfaces 39-41 and an internally thread- .A ed axial passage 42 adapted for threaded engagement with the threaded center portion 43 of the connectorstud 44. As pointed out previously the portion 37 of the side wallV 23 between the exhaust ports33rare integral with and join the rear wall with the forward YportionY of the hub nut.

A connector stud 44 having a conical front portion 45, p v a reduced middle threaded portion 43 and a still further reduced Athreaded rear portion 46 is provided to perform the multiple functions of directing the exhaust gases'to the exhaust ports 33, transmitting to the inner surface V39 of the rear wall 24 the majority of the impact or rearj ward force on the stud 44 resulting from, forV example,

the opening and drag of a parachute and provide means whereby a rearward force may be applied to the hub nut when installed on a torpedo, such as for example, by a parachute or means to remove or aid in the removal Y Y of a steam torpedo from a launching tube. If desired, a y screw driver slot 40 may be provided at the apex of front portion 45 to facilitate insertion or removal of the stud 44.

The apex angle of the conical portion 45 of the stud l portion of the stud is contiguous with and an extension of the rear surfaces 35 of each exhaust port whereby they form a plurality of substantially smooth and continuous conical surfaces. It is desirable that the rear portion `46 of the stud have a diameter less than the center portion 43 to facilitate the formation of the threads thereon. Since-the hub nut as al matter of necessity must rotate with the propeller shaft it is desirable where a threaded connection is used that the rear wall openings 42 and the center portion 43 of the stud be threaded in such a; direction that rotation of the propeller shaft will tend to tighten the stud in the hub nut and that the rear portion.vv Y 46 of the stud be threaded such thatrotation of the hub threaded thereon or, to say it another way, the threads on the rear portion 46 of the stud should be opposite those l on vthe center Yportion 42 of the stud. Such may be expeditiously formed on a stud having the configuration as t described hereinabove although it is to be understood 'Y ofthe hub nut. The longitudinal length of the hub nut t that other obvious configurations will occur to those experienced in the art and it is not intended that the present invention be limited to the stud as shown and described. ForV minimum weight and maximum strength it has been found-preferable to form a hub nut as described'v hereinabove of a lightweight metal such as for example, aluminum or the like and to provide a separate connecting stud as described hereinabove comprised of a metalv having a high shearostrength such as for example, cold rolled steel, stainless steel or the like to provide suicient f shear strength at the connection of the hub nut and the parachute release mechanism. Since most lightweight, metals such as aluminum or the like have a generally lov]V shear strength a stud as described hereinabove is essential for maximum strength and optimum exhaust conditions and also allows simple machining methods and the liketo be used in manufacture of the preferred embodiment;

Itis to be vnoted that if desired the hub nut 10 and stu 44 may be formed as an integral unit. However, in such acase it is necessary that the combined hub nut and stud be comprised of a metal having aphigh shear strength such v as for example, cold rlled steel, stainless steel andthe.;

like. Such a instruction,is` notpreferable sinceitlresults;

in a hub nut weighing; about 66' pereentamore,V than. the preferred embodiment and results inthe requirement of a substantial` change` in the trirn` of the'V torpedo.A since this. weight` is at` thezfur-.thest point from the center-of gravity..

A hub nut incorporating the present ,inventionl may be permanently installed on `or removedV from the propeller shaft of a steam torpedo by utilizing a Spanner wrench having lugs adapted to iit the recesses 47 in the rear surface of the rear wall 24. By rotating the spanner wrench the hub nut may be threaded onto or on le propeller shaft. inadvertent removal or separation of the hub nut from. the. propeller shaft `may be prevented by provision ofr a conventional locking screw 48 threaded into a tapped hole 49 partially in the propeller hub and partially in the hub nut. A parachute harness and its associated release mechanism is attached to the hub nut such as for example by threading the inner sleeve 16 onto the rear stud portion 46 until it abuts the rear surface 41 of the hub nut. Due to the substantial rearward and radial forces present at the point of connection between the hub nut and parachute harness more thoroughly described hereinbefore, it is important that the connecting means, such as for example, sleeve 16, have a substantial forward area and firmly abut the rear surface 41 of the hub nut to prevent bending and consequent failure of the stud at the rear surface of the hub nut.

With regard to air launched steam torpedos it is conventional practice to cause the propeller to be turned by compressed air only during air travel and to begin the hot run after the torpedo strikes the surface of the water and the parachute harness separates from the hub nut.

The hot run of an air launched torpedo, i. e., the turbine prime mover is driven by steam or the like and the steam is exhausted through the hollow propeller shaft, is identical to the hot or normal run of a surface or subsurface launched steam torpedo.

Heretofore the steam was exhausted directly rearwardly somewhat in the manner of a jet thereby resulting in substantial turbulence and noise as the steam impinged against and mixed with the water. A hub nut constructed in accordance with the present invention exhausts the steam in a plurality of initially separate and distinct columns directed in a rotating outwardly and rearwardly direction whereby the steam is dispersed over an area considerably greater than that for conventional steam torpedos thereby resulting in quicker absorption of the steam by -the water and less noise and turbulence than that resulting from a solid steam jet without creating any undesirable back pressure on the turbine or substantially affecting the water exit conditions for which the propeller may have been designed.

It may now be obvious Ithat the present invention may be advantageously used on all steam torpedos without regard to the manner in which they are launched or used. In addition, steam torpedos incorporating the present invention may be air launched with a minimum of modification thereby eliminating the necessity of supplying and stocking means to attach a parachute to a steam torpedo, the unavailability of which means could prevent utilization of advantageous air attacks.

While the present invention has been described in its preferred embodiment it is realized that modifications may be made, and it is desired that it be understood that no limitations on the invention are intended other than may be imposed by the scope of the appended claims.

Having now disclosed my invention, what I claim as new and desired to secure by Letters Patent of the United States is:

1. A torpedo propeller hub nut adapted for use on steam torpedos and the like comprising: a body element open at one end and provided with an annular side wall having a front portion and a rear portion, said side wall having an annular inner surface, said side wall front porwall closing said side wall rear portion andhaving a diameter less `than said side wall front portiongan inclined surface carried by said rear wall, said inclined. surface being axially disposed forwardly of said rear Well; SaidL side wall rear portion being providedwith fa plurality of individualexhaust ports having oppositely disposed iirstand second surfaces, said first surfaces being disposed substantially contiguous withsaidinelined.surface whereby said irst surfaces and said inclined surface provide a plurality of inclined surfaces to receive and direct gases through said exhaust ports'in anl outwardly and rearwardly direction; and connecting means; carried by said rear wall whereby a` rearward force may be applied4 to the said hub nut. Y

2. The combination as described in claim 1 wherein the total area of the exhaust ports :at the annular inner surface is at least as great as the area circumscribed by said annular inner surface.

3. The combination as described in claim 2 wherein said inclined surface is a conical surface and said indi` vidual exhaust ports are formed by concentric oppositely disposed first and second substantially conical surfaces extending in an outwardly and rearwardly direction, the projected apex of said rst surface being substantially coincident with the apex of said conical surface; and third and fourth surfaces, said third and fourth surfaces lying in longitudinal radial planes having a predetermined angle of divergence.

4. The combination as described in claim l wherein said side wall has an inclined router surface having a maximum diameter at its forward periphery and said rear wall is integral with said side wall rear portion and has an inclined front surface extending in an outwardly and rearwardly direction.

5. The combination as described in claim 4 wherein said annular inner surface is comprised of an internally threaded cylindrical front portion and a cylindrical rear portion having a diameter less than that `of said internally threaded front portion.

6. A torpedo propeller hub nut adapted for use on steam torpedos and the like comprising: a body element open at one end and provided with an annular side wall having a front portion and a rear portion, said side wall having an annular inner surface, said side wall front portion being adapted for connection to said torpedo; a rear wall of lesser diameter than said side wall front portion, said rear wall closing said side wall rear portion and provided with an axial passage; and a stud having a substantially conical front portion, a rear portion and a middle l portion adapted for engagement with said rear wall passage, said conical stud portion being axially disposed within said body element and in abutting relationship With said rear wall, -said side wall rear portion being provided with a plurality of individual exhaust ports having substantially parallel first and second surfaces, said iirst surfaces being disposed substantially contiguous with said conical stud portion whereby said first surface and said conical stud portion provide substantially conical surfaces to receive and direct gases through said exhaust ports in an outwardly and rearwardly direction.

7. The combination as described in claim 6 wherein said body element is comprised of a lightweight metal and said stud is comprised of a metal having a high shear strength.

8. A torpedo propeller hub nut for rotatably exhausting the exhaust gases and providing an axial point of attachment for a parachute and the like for steam torpedos provided with a propeller having a hub portion carried by a hollow rotatable propeller shaft comprising: a body element open at one end and provided with an annular side wall having a front portion and a rear portion and forming an extension of said propeller hub, said side wall having an annular inner surface comprised of a front portion adapted for engagement with said propeller shaft l 'i7 ,l 'nd'a cylindricakrear portion having a diameter sub` s'tantially equal. to At'herinternal diameter of saidrpropeller shafhj'a'regar.,` wall closing said sidewall rea'r portion and conical studk portion whereby said first .surfaces and said stud conical portion provide substantiallyconical surfaces 15 2,403,007 Maris .July 2, 1,946V i to receive and directgases through saidexhaust portsv an outwardly and rearwardly direction; u A 7- 9. VThe combinationjas described in claii S'Wherein prised `of a metal having a high shearV strength.

References Cited in the sie of this patent UNITED STATES PATENTS Davis June 9, 1925V lHughes' Aug.` 27, 1940 

